Natural Gas and the
Transformation of the U.S.
Energy Sector: Electricity
Life Cycle GHG Emissions of
Barnett Shale Gas in 2009
Garvin Heath, PhD
Yale Center for Environmental Law and Policy
Seminar series: "Emerging Issues in Shale
Gas Development."
March 5, 2013
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About JISEA
JISEA seeks to guide the transformation of
the global energy economy through
comprehensive, transdisciplinary research
focused on the nexus of energy, finance,
and society.
JISEA Founding
Institutions
NREL
University of
Colorado-Boulder
Colorado School of
Mines
Colorado State
University
Massachusetts
Institute of
Technology
Stanford University
2
Background: Study Goals and Sponsors
•  JISEA designed this study to address four related topics :
–  Life cycle greenhouse gas (GHG) emissions associated with
shale gas compared to conventional natural gas and other fuels
used to generate electricity
–  Legal and regulatory frameworks governing unconventional gas
development at federal, state, and local levels, and how they are
changing in response to industry growth and public concerns
–  Water-related practices of natural gas production companies
–  Electric power futures – Forecasts of demand for natural gas –
and other generating options – in the electric sector under a variety
of policy and technology developments over the next 20 to 40
years
•  Study sponsors: Multi-client sponsor group composed of
natural gas producers, utilities, transmission companies,
investors, researchers, and environmental NGO
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Lifecycle Greenhouse Gas Emissions
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2009 Barnett Shale Gas for Electricity
Goal: Develop an estimate using methods independent of
previous taking advantage of alternative, high
resolution data sets
•  Leveraged Texas Commission
on Environmental Quality
inventories of volatile organic
compounds from NG production
and processing stages
–  16,000+ sources
–  Very high industry participation rates
–  Year 2009
•  Compiled a quality-screened data set of county-level,
extended gas composition analyses of produced (raw) gas
–  Demonstrates wide variability of methane and VOC content within
the Barnett Shale play.
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Methods for Barnett Shale Estimate
For original estimates:
For estimates taken from literature:
•  Venting/fugitives: Methane and CO2
•  Sources: EPA GHG inventory and other
emissions by ratio of inventory VOC and LCAs
county-average composition analysis •  Sensitivity analysis on estimated ultimate
•  Combustion sources: Methane and CO2
recovery of wells and emissions from
emissions by emission factor using
liquids unloading, well completion and
inventory activity data
well workover
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Barnett Shale life cycle GHG emissions
by life cycle phase and GHG
•  Most life cycle GHG emissions attributable to generation of
electricity from combustion at power plant
•  Fuel cycle emissions of both CO2 and methane are important
Multiple estimates, in parentheses, pertain to high EUR, base case EUR, and low EUR, respectively. Single estimates pertain to
stages without sensitivity to EUR. The error bar is plus or minus the total bar length (life cycle GHG emissions).
f
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Barnett Shale Gas Estimate Compared to Harmonized
Literature Estimates for Coal and Conventional Gas
EUR = estimated ultimate
recovery
NGCC = natural gas
combined cycle
Sources: Conventional – O’Donoughue, P.; Heath, G.; Dolan, S. Vorum M.; (2012). “Life Cycle Greenhouse Gas Emissions from Natural
Gas–Fired Electricity Generation: Systematic Review and Harmonization.” Journal of Industrial Ecology (conditionally accepted);
Unconventional – Heath. G.; O’Donoughue, P.; Arent, D.; Bazilian, M. (In Preparation)
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Barnett Shale Gas Estimate Compared to Harmonized
Literature Estimates for Coal, Conventional and Shale Gas
EUR = estimated ultimate
recovery
NGCC = natural gas
combined cycle
Sources: Conventional – O’Donoughue, P.; Heath, G.; Dolan, S. Vorum M.; (2012). “Life Cycle Greenhouse Gas Emissions from Natural
Gas–Fired Electricity Generation: Systematic Review and Harmonization.” Journal of Industrial Ecology (conditionally accepted);
Unconventional – Heath. G.; O’Donoughue, P.; Arent, D.; Bazilian, M. (In Preparation)
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GHG Sources from Barnett Shale
TCEQ Inventories
•  In the Barnett Shale area, many GHG sources
are potentially controllable
aPneumatics,
from the area source inventory, have no count of individual sources
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Loss and leakage of produced gas
Completions
and
Workoversb
Extracted from Ground
Fugitive Losses
Potentially Controllable Leakage
Combusted as Fuel
Production
Processing
Transmissionc
Total
100.0%
100.0%
–
0.1%
0.0%
0.5%
0.6%
0.8%
0.1%
0.0%
0.0%
0.9%
–
0.9%
3.9%
0.8%
5.6%
Delivered to Power Plant
a reported as volume of natural gas consumed or lost per volume of natural gas produced.
b See footnote to Figure 9
c From Skone et al. (2011)
92.9%
•  7.1% fuel cycle loss rate (incl consumed) NG volume per
volume of NG produced (at average EUR = 1.42 bcf).
–  1.5% NG loss per NG produced
–  1.3% methane emitted per NG produced
•  EUR sensitivity:
–  low EUR (0.45 bcf) à 2.8% methane leakage rate; 8.9% loss,
–  high EUR (4.3 bcf) à 0.8% leakage and 6.5% losses.
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Learn More
Download the full report at
nrel.gov/docs/fy13osti/55538.pdf
Learn more about JISEA’s natural gas work at
www.JISEA.org/NaturalGas.cfm
Joint Institute for Strategic Energy Analysis (JISEA). 2012.
Natural Gas and the Transformation of the U.S. Energy
Sector: Electricity. Logan, J., Heath, G., Paranhos, E., Boyd,
W., Carlson, K., Macknick, J. NREL/TP-6A50-55538.
Golden, CO, USA: National Renewable Energy Laboratory.
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Barnett Shale Gas Composition Variability
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Effect of Alternative Gas Composition –
Production and Processing
Denton Countya
Johnson
Countya
Tarrant
Countya
Wise
Countya
22-County Total
Barnett Shale average vs.
main results
12%
-5%
-33%
29%
1%
National average vs. main
results
15%
-11%
-36%
29%
-3%
Denton Countya
Johnson
Countya
Tarrant
Countya
Wise
Countya
Volatile organic compounds
contentd
18%
19%
6%
23%
16%
18%
CO2 contentd
2%
2%
1%
3%
2%
2%
Methane contentd
63%
63%
80%
56%
66%
78%
Barnett Shale
play averageb
National
averagec
a Only
the four top-producing counties in the Barnett Shale play are shown.
average across the 22 counties of the Barnett Shale play
c As reported in EPA (2011)
d Percentage by mass
b Production-weighted
These results have implications for developing more accurate GHG emission
inventories at sub-national levels and any regulatory system that might seek
to identify high emitters within plays.
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Life Cycle GHG Emissions from Generation
Technologies (estimates published pre-2011)
Conventional
gas only
Source: IPCC SRREN, SPM Figure 8.
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GHG Emissions from Production and
Processing
•  Most emissions from CO2
•  Much of emissions is potentially controllable, including
combustion (e.g., higher efficiency)
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